Increase aperture (smaller number numerically) as big as your camera allows. You'll have to increase your shutter speed along with it. Also, the more telephoto you get or the closer you get to your object, the more the background will blur.

For instance,
1. Aperture: F/2.0
2. Shutter: 1/1500
3. Zoom as much as your camera can
4. Stand as close as you can to your bike while still having it fit in the frame.

My GF wants to try and ride trials...I think I'm gonna snag her up one of those.......I don't really like mods, but my GF is 5'0 90 lbs....a mod would prolly be the best thing for her if she wanted to learn.....that, and the Koxx mods are pretty sexy....

Yes...the shirt is pink..... Went out to eat at some steakhouse...my fuckin steak was $70! That didn't include the baked potato or drink or anything...JUST the steak. It was Angus 2 inch beef sirloin or something...it was the best steak I've ever had...but not fuckin worth $70!!!!